Rates of motor seizure development in rats subjected to electrical brain stimulation: strain and inter-stimulation interval effects

Three rat strains were tested at 4 inter-stimulation intervals for the development of motor seizures by repeated amygdaloid stimulation. Wistar rats required a significantly greater number of stimulations to develop motor seizures than did Sprague-Dawley or RVH-hooded rats. There were no significant differences between 24 h, 2 h, or 1 h inter-stimulation intervals with respect to number of stimulations required to develop seizures. There was, however, a significant increase in the number of stimulations required when the inter-stimulation interval was 0.5 h.A second experiment indicated that the retardation of seizure development at short inter-stimulation intervals involved a blockade of the neural changes underlying seizure development and was not simply a result of a blockade of the behavioral expression of those developments. Subjects were pre-treated with a large number of stimulations with short inter-stimulation intervals (15 min). Following a rest period, a subsequent testing period utilizing 24 h inter-stimulation intervals showed that very little seizure development had taken place during the previous period of massed stimulation.